News & Events

Zurich, capital of deculverting

Posted: 12/05/2010

A river revolution has occurred in Zurich, Switzerland. In most cities, many of the small streams and rivers, becks and brooks that would occur in the natural landscape have been culverted; entombed in urban development and hidden beneath city dwellers feet like sewers. This used to be the case in Zurich, but unlike most cities, many of these lost waterways have been resurrected, deculverted by opening them up so that they once again feature in the urban landscape and function as natural streams.

So why has Zurich led this revolution in deculverting? URSULA Project Manager Tom Wild and Consortium Director David Lerner travelled to Zurich to meet local experts to find out the secrets of Zurich’s success. While visiting the city’s rivers, Tom and David were told that one reason deculverting has been so successful in Zurich is that it simply making good economic sense. By removing clean surface water from the combined sewer network, deculverting reduces the amount of water flowing into the water treatment works. With each litre of river water removed from the sewers saving at least 5000 Swiss Francs each year, it is actually more expensive to leave waterways culverted. Of course, it isn’t feasible to dig up vast stretches of the city, so to minimise disruption, deculverting was done in an opportunistic manner, opening up those waterways that occurred at sites of new urban development, and reuniting streams one by one with the cityscape. And there was one more ingredient to the success story; evident by the fact that deculverting hasn't occurred as frequently in other Swiss cities. In Zurich highly motivated individuals lobbied for deculverting, pushing for change against the inertia of embedded traditional practices. Inspiring to know that the sustained efforts of dedicated and passionate individuals can make all the difference!